Interleaved PCAP Touchscreen with Multiple ASICs
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Solution Overview
Problem
Large projected capacitive (PCAP) touchscreens with multiple touch controller ASICs face challenges in complexity and cost due to the need for exchanging and merging raw touch signal data among multiple ASICs, which increases computational intensity and complexity, making it difficult to achieve accurate touch detection and response times.
Innovation Solution
A PCAP touch system with two or more touch controller ASICs connected to a touchscreen in an interleaved manner, where each ASIC calculates coarse touch coordinates independently without exchanging raw mutual capacitance data, reducing the need for inter-ASIC data transfer and simplifying the processing of touch data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple touch controller ASICs are used to support large PCAP touchscreen, then the touchscreen can cover a large number of sensor electrodes, but the system complexity and cost increase due to the need for exchanging and merging raw touch signal data among multiple ASICs
Solution Approach 1:
The touchscreen is divided into multiple zones, with each ASIC independently controlling a specific zone. Each ASIC processes touch data only from its assigned zone, eliminating the need for complex data exchange and merging operations between multiple ASICs. This segmentation approach maintains support for large touchscreen areas while reducing system complexity.
Solution Approach 2:
Each ASIC is configured with zone-specific processing capabilities and parameters optimized for its assigned touchscreen zone. The ASICs use local coordinate systems and processing algorithms tailored to their specific zones, avoiding the need for global data merging while maintaining accurate touch detection across the entire large touchscreen.
2Measurement precision
If multiple touch controller ASICs exchange and merge raw touch signal data, then complete touch detection across the entire touchscreen is achieved, but computational intensity increases
Solution Approach 1:
Touch detection is segmented by spatial zone rather than requiring global data processing. Each ASIC independently detects touches within its assigned zone using zone-specific algorithms, eliminating computationally intensive data exchange and merging operations while maintaining accurate touch detection for each zone.
Solution Approach 2:
Each ASIC performs preliminary touch detection and coordinate calculation independently within its assigned zone before final touch determination. This preliminary action approach allows the system to achieve accurate touch detection without requiring subsequent computationally intensive data merging operations between multiple ASICs.
3Quantity of substance
If multiple touch controller ASICs are used, then the touchscreen can support large number of electrodes, but response time deteriorates due to data exchange and merging requirements
Solution Approach 1:
The touchscreen electrode array is segmented into multiple independent zones, each handled by a dedicated ASIC. This segmentation allows parallel processing of touch data from different zones simultaneously, maintaining fast response times while supporting a large total number of electrodes across all zones.
Solution Approach 2:
Each ASIC independently performs complete touch detection, signal processing, and coordinate calculation for its assigned zone without requiring data exchange with other ASICs. This self-service approach eliminates communication bottlenecks and maintains fast response times while supporting large numbers of electrodes through distributed independent processing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces computational complexity and cost by allowing each ASIC to calculate touch coordinates independently, improving response times and accuracy while minimizing the need for raw data exchange, thus enhancing the performance and efficiency of large PCAP touchscreens.
Implementation Method 1
detect capacitive touch data from touchscreen electrodes
Data Source
AI summary
System, method, and computer program product embodiments are provided for a projected capacitive (PCAP) touch system that includes a touchscreen and two or more touch controller application-specific integrated circuits (ASICs) communicatively coupled to the touchscreen, where connections between receiver (and/or driver) circuits of the two or more touch controller ASICs and touchscreen electrodes are interleaved. The two or more touch controller ASICs do not exchange raw mutual capacitance or self capacitance data during a measurement frame. Further, a processor may be coupled to the two or more touch controller ASICs, and may determine final touch coordinates based on all subsets of coarse touch coordinate data from each of the two or more touch controller ASICs. Embodiments also include determining each subset of coarse touch coordinate data based on a shape of a touch rather than a two-dimensional square or rectangular region of the touchscreen.